An American dream

To many settlers and later immigrants St. Louis became a synonym for the first step into the unknown, but also for an independent future. It took a lot of energy, initiative and confidence in their own abilities to be able to take this risky step and break new ground – the typical American dream. For brewers, this holds true to the present day. The U.S. craft brewers community provides a fascinating and unconventional environment, full of spirits– a hotbed of ideas. This sounded so attractive that a young German brewer and his American colleague, David Wolfe, dared to take the first steps into self-employment. BRAUWELT International talked with Florian Kuplent about his personal American dream.

Global trends in beer bitterness

How bitter are the beers we drink? And how much has the bitterness changed over the years? Although beer production has been growing worldwide for several years now, hops have been used less on average per hl of beer. The trend towards less bitter beers started several decades ago and should be seen in connection with the global distribution of certain brands of beer and the resultant homogenisation of the taste experience. In order to establish how marked this trend is and where it will lead, the Barth-Haas Group began to conduct annual analyses of various brands of beer to examine bitterness in 2006. The results of these analyses are presented in the article below. For the sake of clarity, only the results of the 2009 surveys have been taken.

New insights in hop research

Hops are one of the most interesting areas of research worldwide and all possible applications for hops are far from having been identified. The Barth-Haas Group awards grants for research projects into hops each year. The grants are intended for students who are looking for a topic for their seminar papers, thesis or Master’s thesis dealing with hops and their applications in the brewing industry. The results of the 2008 research are presented below.

The influence of hopping on beer quality

Few topics in brewing science are as controversially discussed as the evaluation and usage of hops. A minimum goal of hopping is the generation of a slight bitter flavour without requirement of any additional sensory properties, though positive side-effects such as light stability for certain bottle types or improved head retention are often noted as desirable characteristics. Hops are also considered to be a spice and the vast range of available hop varieties and possible hopping technologies allow them to contribute significantly to the character and flavour of a beer. The ultimate goal would thus be to strive for an inimitable and singular sensory experience.

Mycotoxins are a diverse range of molecules that are harmful to humans. They are secondary metabolites secreted by moulds, mostly Penicillium and Fusarium. Because of their antimicrobial activity it is most unlikely that hops could be considered a source for mycotoxins. In order to confirm this we again monitored the situation concerning residues of most toxic mycotoxins by screening hops after the last harvest. In our investigations, all major European varieties from different growing areas were considered. To guarantee a representative analysis, ten samples of large lots were selected and then combined into one composite sample for each variety. These results for the 2010 crop are presented in the table below.

Downstream products, such as regular iso extract, rhohydro-iso-, terahydro-iso- and hexahydro-iso extracts, are usually dosed prior to filtration. However in practice some brewers are still adding these extracts after filtration, when there is a distinct risk of precipitation in beer and therefore also of inducing gushing.

For the evaluation of the intrinsic lautering performance of malt an in-house test, predictive for both lauter tun and mash filter operations, has been used. Commercial thermostable endoxylanases added during mashing differ in their ability to increase the filtration rate. Especially the addition of a family 10 endoxylanase at mashing-in can be very efficient in view of wort filtration. Family 10 endoxylanases degrade barley arabinoxylans in an effective way and are not inhibited by the Hordeum vulgare L. xylanase inhibitor (HVXI) purified from barley. Moreover, the addition of this family 10 endoxylanase during germination has a positive effect on the filtration capacity of the kilned malt because the added endoxylanase activity is only partly destroyed during kilning..

Flavour is the significant criterion of evaluation in beer tasting, which depends on many primary and secondary causes. This includes desirable and un-desirable aromatic compounds, but also haptic and physical issues like viscosity, the CO2-level and colour. A beverage for example with a nontypical colour presented in a wrong drinking vessel is always evaluated differently to the “correct” form without any modifications.

Looking to the links and communication in the supply chain, he commented that procurement strategies which place opposing demands on commercial and technical departments are not sustainable. In particular, he identified that the growers, merchants, maltsters and end users who worked closely together were realizing benefits of sustainability that allowed better business management across the cycle. Volatility in prices on the open market resulted from short-term opportunism at various points in the chain. At the extreme, loss of malting barley to export markets, often as feed barley, could results in shortfalls for UK supply – which benefits no-one in the UK market for malt.

The precise determination of Bisphenol A (BPA) amounts in complex matrix like beer is presented. A practical, rapid and reliable sample preparation procedure for BPA determination is shown. The application of stable isotope dilution assay (SIDA) utilizing labmade deuterated BPA standards made it possible to obtain accurate analytical data. BPA concentrations in seven randomly chosen canned beers ranged from 1 µg BPA/L to 6.5 µg BPA/L. Compared to other canned foodstuff these amounts are low and presumably safe.

BrewingScience - Monatsschrift für Brauwissenschaft, 63 (September/October 2010), pp. 122-127

In the beverage industry labels are removed from returnable bottles in bottle cleaning machines. For a successful cleaning process the labels come-off time is crucial. If the labels detach too late in this process, they can block rinsing nozzles and affect the cleaning effectiveness of the machine.